钱塘江水下防护工程的研究与实践

Investigation and application of the underwater protection engineering in Qiantang river

钱塘江河口潮汹流急,破坏力极大,主槽迁徙不定,滩涂冲淤频繁,水下施工十分困难,1968年开始,从涌潮原型观测入手,分析了水下防护建筑物不耐涌潮冲击的原因,提出治江与围涂相结合,变被动防守为主动进攻,抓住滩涂淤涨的有利时机,在滩地上修筑沉井,形成以沉井保护丁坝,丁坝保护盘头、围堤的整体配套水下防护体系,经20年临流考验,成效显著,大大提高了防潮防台风能力,促进治江围涂工程稳定发展,经济效益与社会效益十分巨大。

The funnel-shaped Qiantang Estuary is world-famous for its spectacular tidal bore.The strong tide and torrent have tremendously destructive power,so that the Sea-wall damages and flood calamities often occured during past years.The Sea-wall was fully rebuilt and reinforced after liberation.Therefore,its capability of resisting disaster was increased:As the technical problems arising from underwater protection structures were not yet effectively solved,thus needing a large deal of manpower and material resoures to be used in the course of resisting disaster and protecting Sea-wall.In order to have a better understanding about the crux of tidal flow,to clarify the damage cause,and to find a key to solve the difficult problems of the underwater protection structures,firstly,we had conducted a series of tidal bore prototype observation in 1968 Secondly,according to the characteristics of Qiantang Estuary,we had made the following proposal,i.e.,to combine the river training with the enclosure of the tideland for cultivation,and to shift the efforts of underwater protection into construction on the beach,then to take the method of open caisson for fixing head of spur dike,finally to form such a whole engineering system thereby letting the open caisson protect the spur dike and the spur dike protect the Sea-wall.Having undergone all sorts of flow-conditions for 20 years,the whole protection system was found to be remarkably successful.It is a technical breakthrough,contributing important effects to the river training works and reclamation projects.The economic and social benefits are fairly significant.